Two particle electrophoretic laminate for use with smart windows with reduced diffraction

ABSTRACT

A laminate which can serve as either a smart window or a smart mirror is formed using first and second substrates coated with transparent first and second electrodes which are separated by foraminous layer and a third grid-like linear electrode insulated from the first and second electrodes. The foraminous layer includes spacers defining a cell space which is filled with a colloidal ink having first and second particles. The first particles have a positive charge and a first color and second particles having a negative charge and a second color different from the first color. By altering the voltages of the first, second and third electrodes, one can achieve different light transmission characteristics which, for example, can alter the color temperature of the light transmitted through the laminate or enhance reflective colors.

RELATED APPLICATIONS

The present application is a divisional application of U.S. applicationSer. No. 15/552,924 filed Aug. 23, 2017 as a National Stage Entry ofIntl. Application No. PCT/US15/63390 filed Dec. 2, 2015 claimingpriority to U.S. Application No. 62/095,308 filed Dec. 22, 2014, and62/086,296 filed Dec. 2, 2014. The disclosures of each of theseapplications are hereby incorporated herein by reference in theirentireties.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

The present invention was made with government support under ContractNo. NSF 1231668. The U.S. Government has certain rights in the presentinvention.

BACKGROUND

Light valves used in displays or in smart windows are typically limitedto electronic switching between two states, typically a clear and ablack state. For full-color operation, color filters are utilized whichtypically reduce the optical transmission or reflection by three times.Furthermore, even the clear to opaque switching mechanism can beinefficient itself, further limiting the optical performance to thepoint of preventing commercial success for applications such as smartwindows.

Smart windows are essentially laminates having light transmission orreflectance properties which can be modified. Although smart windows aremost often created using laminate approaches, the layer which modifieslight transmission or reflection properties can also be sandwichedbetween two plates of more rigid glass. The modification of thereflectance or transmission characteristics of the laminate can becaused by physical, electrical, or other stimulus. More specifically,smart glass is glass or a glazing whose light transmission propertiesare altered when voltage, light or heat is applied. There are varioussmart glass technologies, including electrochromic, photochromic,thermochromic, suspended particle, microblind and polymer dispersedliquid crystal devices.

When installed in the envelope of buildings, smart glass createsclimate-adaptive building shells with the ability to save costs forheating, air conditioning and lighting, and avoid the cost of installingand maintaining motorized light screens or blinds or curtains. Mostsmart glass blocks ultraviolet light, reducing fabric fading. Smartglass has limited applications due to the high cost of manufacture andthe limitations with respect to altering light transmission.

Typical methods of forming smart glass are extremely expensive. Further,most smart glass merely changes from transparent to translucent and ismonochromal. Therefore, mechanical blinds or screens can basicallyachieve the same results as smart glass at a significantly-reducedprice. For this reason, there is relatively little motivation to installsmart glass in buildings.

SUMMARY

The present invention provides a laminate covered with electrokineticpixels, or a layer comprising electrokinetic pixels, which utilize afirst transparent layer coated with a transparent planar electrode and asecond layer coated with a second electrode, wherein the two electrodesare separated by a clear foraminous insulating layer. The laminatefurther includes a third grid-like linear electrode separate from thefirst and second electrodes. The cell space between the first and secondelectrodes is filled with a colloidal dispersion having two types ofparticles: the first type of particle having a first color and/or otheroptical property and a positive charge and a second type of particlehaving a second color and/or other optical property different from thefirst and a negative charge. By altering the polarity of the first,second and third electrodes, one can achieve a variety of differentlight transmissive states. By selecting the appropriate particledispersion, one can provide a smart window which provides colortemperature control or one which controls privacy, going from opaque toclear, or one that controls energy, going from opaque toinfrared-absorbing. Other combinations of transmissive or reflectivespectral properties are possible, so long as the two types of particlesdiffer in at least one optical property. Further, if one of the twolayers of the laminate is reflective, the present invention provides asmart mirror which can be turned on and off, changed in color, orsoftened.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an overhead view of the present invention.

FIG. 2 shows an isolated cell broken away from the laminate shown inFIG. 1 according to the present invention.

FIG. 3 is a cross-sectional view of an embodiment of the presentinvention without the colloidal ink.

FIG. 4 is a cross-sectional view similar to FIG. 3 of an alternateembodiment of the present invention without the colloidal ink.

FIG. 5 is a cross-sectional view similar to FIG. 3 showing the K state.

FIG. 6 is a cross-sectional view similar to the embodiment in FIG. 3showing the W state.

FIG. 7 is a cross-sectional view similar to the embodiment shown in FIG.3 in the M state.

FIG. 8 is a cross-sectional view similar to the embodiment shown in FIG.3 in the alternate W state.

FIG. 9 is a cross-sectional view similar to the embodiment shown in FIG.3 in the G state.

FIG. 10A is an overhead view of an alternative hole pattern.

FIG. 10B is an overhead view of a second alternate hole pattern.

FIG. 10C is an overhead view of a third alternate hole pattern.

FIG. 11 is a graph showing percent reflection versus wavelength of anembodiment of the present invention in the W, M, G and K states.

FIG. 12 is a graph of an embodiment of the present invention showingtransmission versus wavelength in the T, R, C and K states, showingtransmissive cyan, red and black states.

DETAILED DESCRIPTION

As shown in FIGS. 1 and 2 , the laminate 10 of the present inventionincludes a first transparent substrate layer 12 and a second substratelayer 14. Substrate layer 12 can be formed from glass or a clearpolymer. Further, layer 12 or layer 14 can be rigid or flexible.

The first substrate layer 12 includes a clear, continuous, planarelectrode 16 made from a transparent material such as indium tin oxide(ITO) and having a thickness of 10 nm to about 100 nm. The firstelectrode layer 16 is then coated with a continuous first insulatinglayer 18, generally having a thickness of about 0.1-10 microns. Thesedimensions set out herein are exemplary.

The second substrate layer 14 can be a clear layer, such as glass, clearplastic or plastic film, or it can be a reflective material if thelaminate is to be used as a mirror. This invention is particularlybeneficial when incorporated into smart glass. Accordingly, in mostembodiments, the second substrate layer 14 will be light transmissive.The second substrate layer 14 includes a second planar, continuouselectrode 20, again formed from a transparent electrically-conductivematerial such as ITO. A foraminous insulating layer 22 is adhered toelectrode layer 20.

The foraminous insulating layer 22 includes a series of pits or holes 24which extend to the electrode 20. Hexagonal, or other geometry, spacers26 separate insulating layer 18 from the foraminous surface of layer 22.The holes 24 are separated from each other by material 28 which formsthe foraminous layer 22. For convenience, we will simply refer to layer22 as a foraminous layer, but that does not limit the present inventionto just hole geometries for the pits or holes. For example, the pits orholes 24 could also be in a mesh or grid geometry, for example by havingthe foraminous layer 22 being a layer of pillars surrounded by a mesh orgrid geometry of no insulating material which would provide the sameeffect of pits or holes 24.

As shown in FIG. 4 , the holes 22 will generally have an averagediameter of 6 to about 10 microns. The holes can be smaller or larger,depending on how much colorant is used.

Spacers 26 form a grid-like pattern. As shown, spacer 26 has aninterconnected grid pattern. As shown in FIG. 1 , this is a hexagonalpattern. But, as explained below, it can be a wide variety of differentpatterns. The spacer 26 defines a plurality of cells 29, again in theshape of hexagons as shown in FIG. 1 . In the embodiment shown in FIGS.2 and 4 , the spacer 26 is coated with a third electrode grid layer 30which is again an electrically-conductive material. This third electrode30, a generally thin, linear electrode forms an interconnected gridpattern and will generally have a width of about 10-100 microns and athickness of about 10 nm to about 10 μm or more, depending on theelectrode material. The third electrode 30 is bonded to the firstinsulating layer 18, thereby defining the individual cells 29 which areclosed. The spacer 26, in combination with the third electrode 30,separate the second electrode 20 from the first insulation layer 18,creating a cell gap 32. Inside the cell gap 32 is a colloidal dispersion34 which includes first colored particles 36 which have a positivecharge and second color particles 38 which have a negative charge, asillustrated in FIG. 5 . As will be taught later, particles can also betransparent, or simply differ from each other in a least one opticalproperty. (The particles are not shown in FIG. 2, 3 or 4 .) The twodifferent particles 36 and 38 have different colors, such asblue/yellow, red/cyan or the like.

The purpose of the insulating layer 18 is to prevent shorting betweenthe third electrode 30 and the planar electrode 16. Therefore, in analternate embodiment the insulating layer 18 could simply be printed orformed onto the third electrode 30 to achieve a similar result. Also, inan alternate embodiment, the planar electrode 16 simply need betransparent as described above, and could therefore be a fine metal meshwhich could provide similar properties of being conductive and opticallytransparent.

The distance between adjacent holes 24 will generally be about 20 toabout 50 microns, in particular, about 30 μm. The thickness of theforaminous layer 22 will generally be 6 to about 30 microns, inparticular, 10 μm. The distance between the first insulating layer 18and the second electrode 20 will generally be from about 6 to about 30,but can be greater. Certain embodiments can be formed with dimensionsoutside these ranges, depending on application and design variable, suchas the type and amount of colorant.

The electrodes 16, 20 and 30 are each attached to a separate voltagesource (not shown) which allows the polarity of each of the electrodesto be changed.

The colloidal dispersion ink located in cell gap 32 is formed from twoparticle types one having a positive charge and a first color orabsorption characteristic and the second having a negative charge and asecond color absorption characteristic. The different particles willgenerally have a particle size of about 100 to about 2000 nm andgenerally 100-800 nm and more particularly 150-700 nm. A dual particlecolloidal dispersion ink is available from Merck Chemicals Limited andis further discussed in Dyed Polymeric Microparticles for ColorRendering in Electrophoretic Displays, SID Symposium Digest, 564 (2010)by M Goulding et al. Others are disclosed in U.S. Pat. No. 7,340,634 andU.S. published applications US2013/0075664 and US2011/0297888.

The colors of the first and second particles will provide differentfunctionalities for the windows. Colors refer to absorptioncharacteristics. Thus, infrared absorbing particles are considered acolor, just not in the visible spectrum. Furthermore, colors can referto another optical property such as optical scattering. For convenience,most of the specification will therefore just simply refer to particleswith ‘colors’ but as discussed above, should not be so narrowlyinterpreted.

If it is desirable to alter the color temperature of the lighttransmission, in other words providing a cooler light or a warmer light,one would choose particles that are complementary in color, particularlyblue/yellow or blue/amber or aqua/amber. Put another way, the firstparticles transmit primarily blue light and the second particlestransmit at least most of red light. If one desires to achieve dimmingand/or privacy of the window, particles which are optically transparentbut scattering, and particles which are optically opaque, could bechosen, for example particles like those used in vertical reflectiveelectrophoretic displays. If energy is a concern, particles which areoptically absorbing in the infrared spectrum can form the firstparticles and particles which are optically absorbing in the visiblespectrum the second particles. This allows one to change the energysavings of a window by blocking various levels of visible or infraredlight transmitted through the window.

The particles are in a fluid carrier, generally a hydrophobic andelectrically insulating fluid such as a hydrocarbon. Suitable carriersinclude commercially-available solvents such as Isopar or Norpar,naphtha, petroleum solvent and long chain alkanes such as dodcane,tetradecane, decane and nonane.

The refractive indices of the various layers, including substrates 12and 14, the colloidal ink and the foraminous layer 22 can affect thewindow operation or optical transmission. If color temperature isimportant, the particles and all the layers in the device should haverefractive indices that are fairly matched, typically close to1.5.+−0.0.2 if the carrier fluid were to have a refractive index of 1.5.The closer the refractive indices, generally the greater clarity of thewindow. If privacy is the main concern, opaque particles and lightscattering particles are used. Refractive index is not as important forthe opaque particles. However, the optically-scattering particle shouldhave a refractive index that is substantially lower or greater than thefluid carrier, and is often greater than 1.7, preferably greater than 2.In particular, metal oxide particles are very good for light scattering.And finally, if energy is a concern, one particle is black in thevisible spectrum and, therefore, the refractive index is not asimportant, while the optically-absorbing particle in the infraredspectrum should be clear and therefore should have a refractive index of1.5.+−0.0.2 or even closer to that of the carrier fluid.

The first and second substrate layers 12 and 14 can be the same ordifferent materials. They can be flexible or rigid. Both can betransparent, or one can be transparent and one reflective if a mirror isformed. In particular, substrates can be glass or a clear plastic, suchas polyolefins, polyesters or polyamides. Further, the substrates 12 andor 14 can include a hermetic layer. The thickness of the substratelayers will vary depending upon the desired application. If a windowpaneis formed, the substrate layers may be glass and should have a thicknessthat provides the effective structural strength required. The laminate10 can be rigid if either or both of the substrates 12 and 14 are rigid.If both substrates are flexible, the laminate can be a film which canthen be adhered to glass to form a smart window or suspended in a frameunder tension to form a smart window.

The insulating layer 18 can be a wide variety of different materials butshould be generally transparent and non-conductive, such as clear screenprintable insulating material typically used in the fabrication ofprinted circuit boards. Other clear plastics or materials can also beused. If the foraminous layer 22 is formed by photolithographicdevelopment, the foraminous layer is a UV-curable polymer which can bedeveloped. One such material is SU-8. If the foraminous layer 22 isformed using a roll-coating process, in other words withoutphotolithographic developing, other materials can be utilized, such asUV curable polymers or thermoplastics including polyesters, polyolefins,polyamides and the like.

The electrode material which forms the third electrode 30 may be clearor opaque. The third electrode 30 can be formed from, for example, aconductive adhesive such as a carbon paste or silver epoxy and thus theelectrode can also act as a binding agent, holding the laminate 10together. The electrode 30, in combination with the spacer 26, will thendefine a closed cell which prevents pigment particles from migratingfrom cell to cell. Alternately, electrode 30 can be aluminum or ITO andcan be printed or photolithographically formed onto insulting layer 18or bonded to insulating layer 18 by an adhesive. In the illustrations,electrode 30 is aligned with spacers 26, but such alignment is not sorequired for achieving control of the particles.

FIG. 1 shows cells 29 with a general hexagonal pattern withevenly-spaced rows and columns of holes 24 as shown in FIG. 2 . Boththis electrode pattern and the spacing the holes can be modified toachieve different results. In particular, FIGS. 10A to 10C show avariety of different patterns of holes 24 through foraminous layer 22.These designs can, for example, reduce diffraction relative to a patternof uniform rows and columns of holes. The pattern shown in FIG. 10A hasnine different hexagonal patterns rotated at different angles. Thismimics a moth's eye to reduce diffraction pattern. The pattern shown inFIG. 10B is a very high symmetry pattern based on a sunflower seedarrangement with multiple spiral rows of holes. The resultingdiffraction pattern is circular with no strong underlying lower symmetryorders. FIG. 10C shows a Conway pinwheel hole pattern. All of thesepatterns provide increased suppression of backscatter diffraction orforward diffraction.

The third electrode 30 is an electrode grid which can be formed in avariety of different grid patterns in addition to hexagons. The gridpattern can, for example, be interconnected triangles, interconnectedrectangles, random intersecting ovals and the like or even a series ofstraight linear parallel electrodes, which may be periodically connectedto each other. The shape of the cell pattern can be varied to affectlight transmission characteristics and/or to avoid effects such asoptical diffraction. To minimize optical diffraction, the grid patterncould be in the form of a tessellated non-Euclidean pattern. Becauseelectrode 30 is a grid, if there is a single break anywhere, it willhave no impact because the grid pattern provides multipleelectrically-conductive paths.

The laminate 10 can be formed using various different processes. In theembodiment shown in FIGS. 3, 5, 6, 7, 8 and 9 , the substrates 12 and 14are coated with the planar electrodes 16 and 20 and insulating layer 18using standard coating techniques. The foraminous layer 22 can beapplied as a continuous coating, with the holes 24 subsequently formedby photolithographic means. The grid electrode 30 is applied directly toinsulating layer 18, using a coating process. The individual cells arethen dosed with the colloidal ink. The two layers are adhered togetherby bonding spacers (not shown in these FIGS.), which extend up fromforaminous layer 22 to insulating layer 18, establishing the cellpattern.

The embodiments shown in FIGS. 2 and 4 are formed without use ofphotolithographic etching. The first and second substrate layers 12 and14 are coated with, for example, indium tin oxide to form the first andsecond electrodes. The first electrode is then coated with an insulatinglayer 18, again using standard coating techniques. The foraminous layer22 is formed using roll to roll micro-replication of the holes 24 andspacers 26.

Contact printing, roller printing or other simple transfer methods areused to coat the spacer 26 with the material which forms the thirdelectrode 30. This electrode material can be a conductive adhesive suchas a silver epoxy. Alternately, the third electrode can be formed from,for example, indium tin oxide or aluminum and then coated with anadhesive. Alternately, the third electrode can be formed from, forexample, aluminum and then coated with an adhesive with spacer balls orother spacer particles which eliminate the need for the insulating layer18 because the adhesive could act as the insulation layer. The colloidalink is dosed into the individual cells and sealed by binding theinsulation layer 18 to the electrode 30, forming individual close cellswith a defined cell gap. Alternately, the spacer 26 and electrode 30could be unified in the form of a wire mesh that is coated with anelectrical insulator, or any other equivalent material or element thatcould form an effective grid electrode 30 that is electrically insulatedfrom electrode 16 and electrode 20.

The electrodes 16, 20, 30 are then attached to the three differentvoltage sources (not shown). A conductive adhesive can be used toseparately connect the three electrodes to three separate voltagesources.

In use, the voltages of the three electrodes can be individuallypositive, negative or neutral. FIGS. 5 to 9 show the various operationsof the present invention. In these examples, the negative particles weregreen, and the positive particles were magenta. By varying the variousvoltages, five different states labeled K (black), W (white), M(magenta), Alternate W (white) and G (green) were achieved.

K State: As shown in FIG. 5 , the initial state with no voltages appliedis opaque as the particles spread evenly over time in the absence ofvoltage. Actively switching to the black state will be described at theend of this section.

W state: as shown in FIG. 6 , starting from the previous K state, a Wstate is achieved by setting the bottom ITO electrode 20 to −25V and thehexagonal third electrode 30 to +25V, and the top first electrode 16 iskept at 0V. As a result, negatively charged green particles 38 arecompacted at the hexagonal electrode 30 and the magenta particles 36 arecompacted in the holes 24. After the switching is adequately complete(˜10 s) this state can be maintained with voltages of less than 10V.

M state: M state is shown in FIG. 7 . M state is achieved from theprevious W state by switching the bottom ITO electrode 20 to +25V andthe top ITO electrode 16 to −25V which then draws the magenta particles36 to a spread state on the top plate 12, while the hexagonal electrode30 is still maintained at the same +25V from previous state, retainingcompaction of the green particles 38. The switching is complete asperceived by the naked eye at a distance, in (˜10 s) and can bemaintained at a low holding voltage of +/−10V.

Alternate W state: The alternate W state as shown in FIG. 8 is where thenegatively charged green particles 38 are compacted in the holes 24 bysetting the bottom electrode 20 to +25V and compacting the magentaparticles 36 to the hexagonal electrode 30 by setting it to −25V whilekeeping the top ITO electrode 16 at 0V. For optimal optical performance(most complete particle movement), it is best to leave the M state,return to the original W, then actively to the K state (see sectionbelow), then finally switch to the alternate W state. Again, this statecan be maintained at a low holding voltage of +/−10V.

G state: The G state as shown in FIG. 9 is set from the previous W stateby reversing the bottom ITO electrode 20 to −25V while the top electrode16 is switched to +25 V which moves and spreads green particles 38 tothe top. The hexagonal electrode 30 is kept at the same potential of−25V from the previous state which still holds the magenta particles 36in their place. This state can then be maintained at a low holdingvoltage of +/−10V after the switching is complete in ˜10 s.

Actively Returning to the K state: A multi-step process is neededsimilar that needed for the alternate W state, for optimal opticalperformance (most complete particle movement). It is best to first leavethe G state by returning to the alternate W state. Then the K state canbe achieved within ˜7 s by spreading the particles 36 and 38 byrepeatedly reversing voltage between the bottom electrode 20 and theelectrode 30 (FIG. 1 ), followed by removing all the voltages. Completemixing is difficult to quantify and is achieved only after the voltagesare removed for 10 s.

A laminate having a red cyan dispersion was prepared and thetransmission spectra was measured, and the results are shown in FIG. 11. In this embodiment, substrates 12 and 14 are clear. The lighttransmission through the laminate in the transmissive, cyan, red andblack states are shown. The reflective spectra of a device formed with agreen/magenta particle dispersion is shown in FIG. 12 . In thisembodiment, substrate 14 is reflective. The light reflected in thewhite, green, magenta and black states are shown.

Thus, the present invention provides a three electrode electrokineticdevice with dual charges, dual color colloidal dispersion ink for smartwindows or smart mirrors. This laminate adds the ability to switchpixels into multispectral states, improving color performance inreflective displays and providing color temperature control for smartwindows. Further, the structure allows for simple fabrication usinglow-cost large area fabrication techniques, allowing the laminate to beformed inexpensively and thus expanding its potential applications.

In one embodiment, the hole pattern of foraminous layer 22 can be usedto reduce diffraction in a device using a fluid with only particles ofthe same charge. In this embodiment, the foraminous layer 22 (in eitherof the embodiment shown in FIG. 2 or 3 ) has a hole pattern whichreduces diffraction. The laminate 10 includes a colloidal dispersionwith particles with the same charge. By applying a voltage to electrode20, the particles (not shown) would fill holes 24 and thus reducediffraction without altering other optical properties. Further in thisembodiment, the third electrode 30 would be unnecessary. As previouslyindicated, exemplary hole patterns which reduce diffraction are shown inFIGS. 10A-10C. Also has discussed previously, the geometry of the spacerlayer can also be adjusted to prevent diffraction. In particular, atessellated non-Euclidean pattern can be employed.

Therefore, the devices demonstrated here, along with an improvedblue/yellow dispersion, could provide the first ever smart windowcapable of both dimming light transmission, and alter the colortemperature of transmitted light. The yellow-state could even beamber/orange tinted, which would improve the opacity of the black state.Further, the laminate can be designed to reduce or eliminatediffraction.

In an alternate embodiment of the present invention, particles dispersedin the fluid can have the same polarity of charge, but differentelectrophoretic mobilities or zeta potentials. For example, a firstparticle could have a similar average size as a second particle which isof different color, but the first particle would have twice the amountof electrical charge. Therefore, the first particle would have a lowervoltage threshold for movement which may be referred to as a firstthreshold voltage. The second particle would have a greater thresholdvoltage for movement referred to as a second threshold voltage.Therefore, if only the first threshold voltage was applied, the firstparticles would substantially move whereas the second particles wouldnot. If the second threshold voltage were applied, both the first andsecond particles would move, with the first moving more quickly. As aresult, the variations of colors and mixed colors and optical states ofthe present invention can be achieved without two particles of oppositepolarities. Such a configuration could also allow operation of thepresent invention without the third electrode, by, for example, byvoltage thresholding of which particles are spread or compacted.

This has been a description may different embodiments of the presentinvention. However, the invention itself should be defined by theappended claims wherein we claim:

What is claimed is:
 1. A laminate including electro kinetic pixelscomprising: a transparent first layer coated with a planar firstelectrode; a second layer coated with a planar second electrode; aforaminous insulating third layer between said first layer and saidsecond layer; a third electrode having a grid structure; a cell gapbetween said third layer and said second electrode; said cell gapincluding a colloidal dispersion of first particles and secondparticles; said first particles having a first charge and a firstoptical property; said second particles having a second charge differentfrom said first charge and a second optical property different from saidfirst particles; wherein said third electrode is separated from saidfirst electrode and said second electrode; and wherein said gridstructure comprises a plurality of tessellated electrodes with anon-Euclidean geometry.
 2. The laminate of claim 1, where said firstcharge has a positive polarity and said second charge has a negativepolarity.
 3. The laminate of claim 1, where said first charge isdifferent in magnitude than said second charge, such that said firstparticles and said second particles have different voltage thresholdsfor movement.
 4. The laminate of claim 1 further comprising aninsulating layer adjacent said first electrode, and wherein said thirdelectrode is on a side of said insulating layer opposite said firstelectrode.
 5. The laminate of claim 1 further comprising an electricallyinsulating adhesive between said first electrode and said thirdelectrode.
 6. The laminate of claim 1 wherein said third electrode is aconductive adhesive binding said laminate together.
 7. The laminate ofclaim 1 wherein said first layer is transparent, said first electrode istransparent, said second layer is transparent, said second electrode istransparent, and said laminate is a smart window.
 8. The laminate ofclaim 1 wherein said first optical property is opaque and said secondoptical property is transparent to visible light and absorbs infraredlight.
 9. The laminate of claim 1 wherein said first optical property isopaque and said second optical property is optically scattering to avisible light spectrum.
 10. The laminate of claim 1 wherein said firstoptical property and said second optical property are colors.
 11. Thelaminate of claim 1 wherein said first optical property is a color andsaid first particles transmit primarily blue light and wherein saidsecond optical property is a color and said second particles transmit atleast most of red light.
 12. The laminate of claim 1 wherein said firstoptical property and said second optical property are colors that arecomplementary.
 13. The laminate of claim 1 wherein said third layerdefines a pattern of holes that does not have repeating rows and columnsof holes.
 14. The laminate of claim 13 wherein said pattern of holes hasmultiple spiral rows of holes.
 15. The laminate of claim 13 wherein saidpattern of holes forms a Conway pinwheel pattern.
 16. The laminate ofclaim 13 wherein said cell gap between said third layer and said secondelectrode is supported by a spacer layer.
 17. The laminate of claim 1wherein said laminate is flexible, and wherein said laminate is adheredto a glass panel.
 18. The laminate of claim 1 wherein said first layerand said second layer are glass.
 19. The laminate of claim 1 wherein oneof said first layer and said second layer is rigid and the other of saidfirst layer and said second layer is a flexible film.
 20. The laminateof claim 1 wherein said third layer defines a continuous spacer andwherein said third electrode is on a top surface of said continuousspacer, wherein said continuous spacer defines a plurality of closedcells.
 21. The laminate of claim 1 wherein said third layer comprises amesh pattern.